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TitleGeology and mineralization of the link between Hope Bay and Elu Greenstone Belts, northeastern Slave Craton, Nunavut
AuthorMvondo, H; Lentz, D; Bardoux, M; James, D T
SourceGeological Survey of Canada, Open File 7007, 2012, 58 pages,
PublisherNatural Resources Canada
Documentopen file
Mediaon-line; digital
File formatpdf
ProvinceNorthwest Territories
AreaBathurst Inlet; Four Lakes
Lat/Long WENS-108.0000 -106.0000 68.0000 67.0000
Subjectseconomic geology; igneous and metamorphic petrology; structural geology; stratigraphy; geochemistry; Archean; bedrock geology; igneous rocks; metamorphic rocks; metabasalts; iron formations; metasedimentary rocks; deformation; greenstone belts; mineralization; alteration; Bathurst Block; Slave Craton; Hope Bay Greenstone Belt; Elu Greenstone Belt; Precambrian
Illustrationslocation maps; tables; plots; photomicrographs; stereonets
Natural Resources Canada Library - Ottawa (Earth Sciences)
ProgramCanada-Nunavut Geoscience Office, Funding Program
Released2012 02 27
AbstractLocated in the NE Bathurst Block of the Slave Craton, the Hope Bay and Elu belts are two Neoarchean greenstone belts striking N-S and NE-SW, respectively. The Elu Belt (EB) southern end is deflected westwards to form a concave connection termed the Elu Link (EL) where 2716 to 2663 Ma supracrustals are in part shared with the adjacent Hope Bay Belt (HBB). The EL supracrustal sequence consists mainly of tholeiitic pillowed metabasalts with lesser amounts of interleaved metadacite, metarhyolite, iron formation, and metashale, having variably recorded D1 - D3 deformation. Supracrustals appear to be seamlessly in contact with syn-D1 migmatite orthogneiss on the EL eastern margin. Orthogneiss and supracrustal rocks were both intruded by syn- to late-D2 metagabbros and metagranites. Like in the HBB, Archean magmatic rocks of the EL originated from deep and upper mantle sources in a probable back-arc setting. Sparse NE-striking Proterozoic dolerite dikes derived from deep mantle sources cut the entire rock mass. D1 deformation was successively accompanied by hydrothermal alteration and prograde metamorphism reaching epidote-amphibolite facies peak conditions, but related structures are strongly obscured by D2 + D3 overprint. D2 that initiated under prograde metamorphism and was further accompanied by greenschist retrogression deformed D1 fabrics around tight to open curvilinear F2 folds forming a foliation triple junction between the EB + HBB. The F2 folds together with L2 radial stretching lineation and coeval shear zones show that the EL is rimmed around a syn-compression large-scale D2 dome. D3 is a brittle-ductile deformation lacking any visible fabric. Both D2 + D3 denote vertical general flattening dominated transpression with E-W maximum compression and N-S minimum extension. They illustrate asymmetric syn-compression exhumation of the HBB and EB that were further affected by strain-free greenschist retrogression due to the Thelon Orogeny. The mineralization comprising Au-As-Cu-Zn metals in most EL rock units occurred prior and, possibly, during metamorphism, was further remobilized by subsequent tectonic and thermal events. It follows that ore mineralization occurrence in the EL is chiefly lithologically and structurally controlled.